The invention relates to a medium-bore training cartridge for an automatic rapid-fire weapon and also a system based on such a training cartridge and a weapon barrel.
For training purposes, it is necessary to have at one's disposal training and maneuver ammunition, the features of which correspond to live ammunition, at least where rapid-fire weapons are concerned, so that all functions can run smoothly. It must not be necessary in this regard to make any essential modifications to the weapon. At the same time, the training cartridge and any necessary conversion kit for the weapon must be configured in such a way that live ammunition cannot inadvertently be fired whilst shooting with maneuver ammunition.
German Patent No. DE-A-14 53 827 proposes to equip the training cartridge with a bore hole, which is closed off above the propellant charge arranged in the rear area and if necessary in the area near the cartridge tip by a destructible cap. If the cover(s) is (are) correctly dimensioned, the cartridge, when fired, is followed by an initial shock dust, which is sufficient to guarantee a recoil of the barrel when the weapon bolt is reversed. The covers are subsequently destroyed by the propellant charge and leave the barrel before the cartridge, the speed of which is reduced due to the presence of the continuous bore hole.
This type of training cartridge however does not guarantee to prevent live ammunition being inadvertently fired.
German Patent No. DE-A-37 33 216 discloses a weapon barrel for automatic weapons for the purposes of firing training ammunition, particularly blank cartridges, whereby a limiting bush is secured near a cartridge bearing and the weapon bolt inside the barrel and a nozzle insert is secured as a gas choke near the muzzle in the front part of the barrel. This limiting bush must be configured so as to prevent a live cartridge being fully pushed into the barrel, which ensures that the weapon will remain fully operable in this case. Training ammunition, which is simply modified to be thinner near the cartridge tip can be inserted so far into the limiting bush that the cartridge is completely accommodated by the barrel.
When firing blank cartridges, this barrel, which is preferably a de-commissioned barrel that has been modified for use with live ammunition, is replaced by a barrel suitable for firing live ammunition. The use of a nozzle insert, which if necessary has an adjustable tuyere area, creates a gas pressure in the barrel that is both necessary and adequate for automatic weapon function when a training cartridge is fired. This gas pressure guarantees both the locking function and ejection of the cartridge. The blank cartridge does not leave the barrel, the bang, smoke and possibly the flash from the muzzle are simply simulated when the blank cartridge is loaded.
This system can be applied to small-bore training ammunition. It does however require structural modifications to the barrel and the training ammunition.
Moreover, it is extremely difficult to achieve the gas pressure required for medium-bore rapid-fire weapons with this system. With conventional 40 mm training cartridges, gas pressures able to release the weapon bolt, which weighs approximately 7 kg, must be provided.
German Patent No. DE-A1-41 34 505 discloses a small-bore cartridge for simulated firing using a laser beam, which has a bush with longitudinal bore hole, whereby the external form of the bush corresponds to that of a standard cartridge case containing a cartridge. Release of a weapon bolt is also not possible with this cartridge.